The rapidity with which railways are built in the United States and Canada contrasts strongly with what has been done in other countries. Much has been written of the energy of Russia in building 3000 miles of Siberian railway in five or six years. In the United States an average of 6147 miles was completed every year during ten successive years, and in 1887 there were built 12,982 miles. The physical difficulties overcome in Siberia are no greater than have been overcome here. This rapid construction is due to several causes, the most potent of which has been the need of extending railways over great distances with little money. Hence they were built economically, and at first in not as solid a manner as those of Europe. Steeper gradients, sharper curves, and lighter rails were used. This rendered necessary a different kind of rolling-stock suitable to such construction. The swivelling-truck and equalizing-beam enabled our engines to run safely on tracks where the rigid European engines would soon have been in the ditch. Our cars were made longer, and by the use of longitudinal framing much stronger. A great economy came from the use of annealed cast-iron wheels, with hardened tires, all in one piece, instead of being built up of spokes, hubs, and tires in separate parts. These wheels now seldom break, and cost much less than European wheels. As there are some eleven million car-wheels in use in the United States the resulting economy is great. It was soon seen that longer cars would carry a greater proportion of paying load, and the more cars that one engine could draw in a train, the less would be the cost. It was not until the invention by Bessemer in 1864 of a steel of quality and cost that made it available for rails that much heavier cars and locomotives could be used. Then came a rapid increase. As soon as Bessemer rails were made in this country, the cost fell from $175 per ton to $50, and now to $26. Before that time a wooden car weighed sixteen tons, and could carry a paying load of fifteen tons. The thirty-ton engines of those days could not draw on a level over thirty cars weighing 900 tons. The pressed steel car of to-day weighs no more than the wooden car, but carries a paying load of fifty tons. The heaviest engines have now drawn on a level fifty steel cars, weighing 3750 tons. In the one case the paying load of an engine was 450 tons; now it is 2500 tons. Steep grades soon developed a better brake system, and these heavier trains have led to the invention of the automatic brake worked from the engine, and also automatic couplers, saving time and many lives. The capacity of our railways has been greatly increased by the use of electric block-signals. The perfecting of both the railway and its rolling-stock has led to remarkable results.